The radio field intensity of a frequency of the microwave band or higher is influenced by a weather situation such as rain, fog and humidity greatly, and it is known that, in the submillimeter wave zone and the millimeter wave zone of 10 GHz or more in particular, a radio field intensity attenuates greatly by rainfall and snowfall. For example, according to non-patent literature 1, relation between an attenuation factor γR (dB/km) and a rainfall amount R (mm/h) per a unit time is expressed in following equation (1).γR=kRα  (1)Here, k and α are coefficients that depend on a frequency of a radio wave. Attenuation of radio field intensity caused by such weather situation degrades wireless line quality, and, thus, various kinds of technologies to suppress or evade such influence have been proposed.
For example, in a radio apparatus disclosed in patent literature 1, a sensor which acquires weather information such as rainfall, snowfall and humidity is provided, and a radio frequency and a modulation method are controlled according to the acquired weather information so as to achieve good communication quality. In a line band controller disclosed in patent literature 2, a rainfall intensity distribution and a moving speed are estimated from rainfall information obtained in advance, and a line band is controlled so that deterioration of wireless line quality by this may be evaded.